Photographic color correction



March 22, 1955 w HANSON, JR 2,704,711

PHOTOGRAPHIC COLOR CORRECTION Filed June 28, 1952 UIVEXI'USED| EXPOSED PALKETS colvmwm/e couo/o/u 75 l g l SILVER AND nnemm-ramws COUPLER SILVER HAL/DE E/WULS/O/V COMM/MING MAGENTA-FORMING COUPLER SILVER HAL/DE EMULS/O/l C0/vT4/ll/NG CYAN-FORMl/VG COUPLER SUPPORT AFTER cow/e azvaopnavrm/ COLOR DEVELOPER CONTAIN/N6 SILVER HAL/0E SOLVE/V7, AND SILVER REMomL MAGENM POS/77VE/MA6E YELLOW NEGATIVE IMAGE MAGE/WA NEGATIVE IMAGE NEGATIVE IMAGE l6 Wesley THanson, J1."

INVENTOR.

BY Q ZWZM ATTOIENEZKS' United States Patent PHOTOGRAPHIC COLOR CORRECTION Wesley T. Hanson, Jr., Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application June 28, 1952, Serial No. 296,175

4 Claims. (Cl. 95-2) This invention relates to photography and particularly to a method for securing color correction in color trans parencies used for printing.

It is known that dyes used in subtractive multi-color photographic pictures do not transmit all of the light which theoretical considerations demand. The cyan dye which should absorb red light and transmit green and blue light usually absorbs a small amount of green and blue light as well as a major proportion of red light. The magenta dye which should absorb green light and transmit blue and red light usually absorbs a considerable amount of blue light and a small amount of red light. The yellow dye which should absorb blue light and transmit green and red light is usually satisfactory although sometimes it absorbs a small amount or" green light. The result of printing a multi-color picture formed of such dyes is to introduce unequal parts of all three records in each image which is made, regardless of the color of light used in printing or the sensitivity of the printing material employed. Correction of the colors on printing is therefore desirable, and this is usually done by masking, as described in prior patents, such as Evans U. S. Patent 2,203,653, granted June 4, 1940, and my prior Patent 2,294,981, granted September 8, 1942.

An integral colored mask is now generally considered to be the most desirable type and a method of producing such masks from colored couplers is described in my prior Patent 2,449,966. These masks have, however, one drawback. Being colored prior to exposure, they absorb part of the exposing light. When incorporated in lower layers of a multi-layer coating this is not serious, but such colored couplers cannot ordinarily be used in the top layer of a multi-layer coating. A blue-sensitive emulsion layer in which a yellow dye image is formed is ordinarily used as the top layer and the masking dye should be green-absorbing to correct for the undesired green light absorption of the yellow dye. A green-absorbing dye would, however, prevent exposure of the lower green-sensitive layer.

It is therefore an object of the present invention to provide an automatic photographic masking method in which one or more of the emulsion layers is uncolored prior to development. A further object is to provide a novel integral masking film and process. A still further object is to provide a masking method in which the yellow dye image may be masked without coloring the bluesensitive emulsion layer prior to development. Other objects will appear from the following description of my invention.

These objects are accomplished by incorporating an uncolored image-forming coupler in the emulsion layer in the usual way and also incorporating in the layer packets or particles of water-insoluble colloid containing physical development nuclei and an uncolored masking coupler. Upon development of the exposed emulsion in a solution of a primary aromatic amino developing agent containing a silver halide solvent a negative O-o 0011.0 ONE dye image is formed from the image-forming coupler and at the same time a positive masking image is formed from the masking coupler by physical development of the dissolved silver halide positive image on the physical development nuclei.

The accompanying drawing illustrates in sectional view a film at various stages in my process.

In making an emulsion according to my invention conventional gelatino-silver halide emulsions and colorless coupler are employed. As is well known, the dyes formed from these couplers are not perfect in light absorption characteristics but absorb some light in regions in which absorption is undesirable. The cyan dye absorbs a major proportion of light in the red spectral region and a minor proportion of light in the green and blue spectral regions. The magenta dye absorbs a major proportion of light in the green spectral region and a minor proportion of light in the blue spectral region. The yellow dye absorbs a major proportion of light in the blue spectral region and a minor proportion of light in the green spectral region. It is the intent of masking to overcome this undesirable absorption by forming a positive image (if the image-forming dye is a negative) which absorbs an amount of light in the minor absorption region of the image-forming dye, equal to that absorbed by the image-forming dye in that region.

The couplers used according to my invention may be incorporated in the emulsion as described in Mannes and Godowsky U. S. Patent 2,304,940 or Jelley and Vittum U. S. Patent 2,322,027, or they may be directly incorporated as described in Fisher U. S. Patent 1,102,028.

Packets or particles containing the masking coupler are made from a colloidal material which is insoluble in water at or below room temperature and in the gelatin of the emulsion. The preferred colloid is a styrenemaleic anhydride resin which has been amidated and converted to the ammonium salt as described in Examples 2 and 3 of Godowsky U. S. application Serial No. 156,066, filed April 15, 1950. Other styrene-maleic acid or anhydride polymers or copolymers may be used as well as polymers of styrene with other cap-unsaturated carboxylic acids such as styrene-acrylic acid, styrenemethacrylic acid and styrene-itaconic acid, algin, oxidized cellulose, polymethyl acrylic acid, polyethyl acrylic acid (Godowsky U. S. Patent 2,548,526), and hardened gelatin (Baines et al., U. S. Patent 2,618,553) may also be used. I

The physical development nuclei include colloidal silver, gold and silver sulfide.

The masking coupler or couplers may be present in one or more of the layers of a three-layer coating. For example, there may be a magenta masking coupler in the yellow layer, a yellow masking coupler in the magenta layer or a mixture of yellow and magenta masking couplers in the cyan layer. By yellow, magenta and cyan layers I mean the layers in which the yellow, magenta and cyan image-forming dyes, either negative or positive, are formed by development after exposure. The masking couplers may be present in one, two or all three of the emulsion layers. Also, the couplers in one or two of the layers may be colored couplers as described in my U. S. Patent 2,449,966, and the other layer or layers may contain a dispersed colorless masking coupler according to the present invention. For example, colored couplers might be used for masking purposes in the cyan and magenta layers and a colorless masking coupler in the yellow layer as described in the present application.

The following couplers are suitable for use according to my invention:

Yellow-forming couplers N- 4-benz oylacetaminobenzenesulfonyl) -N-'y-pheny1propyl) p-to1uidlne O CHIC ONE-Q NHCO 3 (3-p-tert. amylphenoxybenzoylamino) l-benzoylacetaminobenzene O0 OCH-C ONE 4- (a-2-methoxybenzoyl-a-chloracetamido) -2' ',4"-dl-tert. amylphenoxyacetanmde Magenta-forming couplers .-tert. bu l heno henyl-3-a-(p.-tert. hutylphenoxy- 1 (p p i opton y lan lno)-!S-pyrazolone 1- tert. bu lheno henyl -3-[3'-(p-tert. amylphe- (F ii xyr enzoy l nlnol- -py1azolone 1- 2 4 6'-trichloro henyl -3-[3"- 2"'.4"'-d1-tert. amyl- 'p enoxyacetainldoybenzami 01-5-pyrazolone Cyan-forming couplers NHCOCHr-O-Q-Csliu 2-(diamylphenoxyaoetamino)4,6-dlchloro-5-methylphenol C0NH(CHa)4-OOC5H11 1-h dro -2- A- 2,4-di-tert. amy1phenoxy)-n-buty1]- y W I naphthamlde HaC (I) HIGOCHQ-N-O O CsHu (sec) In making a three-layer coating, the first two emulsion layers were made as describedin Example 7 of Jelley and Vittum 'U. S. Patent 2,322,027. These layers were coated in order on the usual cellulose ester film support and were followed by a layer of colloidal silver in gelatin NBC oom-o-Ootm NEG o om-OQ-cml and then by a blue-sensitive emulsion layer containing a yellow-forming coupler and a dispersion of a magenta masking coupler made as follows:

The magenta coupler dispersion was made by dissolving 22 grams of the coupler 1-(2',4',6'-trichlorophenyl)- 3-[3"-(2"',4"'-di-tert. amylphenoxyacetamido) benzamidoJ-S-pyrazolone in 64 cc. of dibutylphthalate at 150 0., adding the solution to 45 cc. of a 5% solution of Alkanol B dispersing agent in 326 cc. of 10% gelatin solution and dispersing it therein. A concentrated dispersion of colloidal silver in gelatin was made and 31.2 grams of the colloidal silver dispersion and 112 grams of the magenta coupler dispersion were added to 62.3 grams of 10% gelatin solution, and then cc. of a 15% solution of a copolymer of methacrylic acid and methyl-u-methacrylate (sodium salt) were added to the mixture and the mixture was stirred at 40 C. for thirty minutes.

At the end of the stirring, 45 cc. of a 5% solution of the ammonium salt of styrene-maleamic acid polymer was added and the stirring continued for 45 minutes during which time packets were formed. In order to insolubilize any unreacted polymer, 15 cc. of a 10% solution of calcium acetate and 80 grams of gelatin were added to the packet mixture. This mixture was then added to an unsensitized negative-speed gelatino-silver bromide emulsion containing 9.6 grams per liter of the yellow coupler, N-(4-benzoylacetaminobenzenesulfonyl)-N-(-y-phenylpropyl)-p-toluidine, which had been dispersed in dibutylphthalate and incorporated in the emulsion as described in Jelley and Vittum U. S. Patent 2,322,027. The packets ranged in size from about 5 to about 7 microns.

Example 2 A film was made by coating on the usual cellulose ester film support successive layers of red-sensitive emulsion containing cyan coupler and green-sensitive emulsion containing magenta coupler made as described in example col. 6 of my prior Patent 2,449,966, but using as the cyan coupler Z-(diamylphenoxyacetamino)-4,6- dichloro-S-methylphenol and as the magenta coupler 1 (p tert. butylphenoxy) phenyl 3 a- (p-tert. butylphenoxypropionylamino)-5-pyrazolone. The green-sen sitive layer containing the magenta coupler was followed by a layer of colloidal silver in gelatin and a blue-sensitive layer made as described in Example 1.

These coatings, upon exposure, may be developed in a color-developing solution containing a silver halide solvent, for example, a solution of the following composition:

4 amino N ethyl-N-p-methylsulfonamido ethylm-toluidine grams 5 Sodium sulfite o 40 Sodium carbonate,monohydrate do 50 Potassium bromide d 1 Benzyl alcohol c 6.5 Sodium hydroxide ..-grams 0.5 Water to 1 liter. pH 10.75.

After color development, the films are fixed, washed, bleached, fixed and washed in the usual way.

The developing solution above contains a high content of sodium sulfite which acts as the silver halide solvent. Other silver halide solvents which may be used include sodium thiosulfate, ammonium thiosulfate, amines, such as ethylenediamine, isopropyl amine etc.

The developer may be made up as a dry composition using potassium, lithium, or sodium benzyl carbonate instead of benzyl alcohol. Potassium benzyl carbonate,

These ingredients are mixed with water to make one liter of solution and pH adjusted to 10.75 by the addition of sodium hydroxide or sulfuric acid as required.

Potassium benzyl carbonate was made as follows:

A solution of 20 grams of potassium hydroxide in 200 cc. of benzyl alcohol was diluted with 900 cc. ligroin and carbon dioxide was passed into the solution. Plate-like crystals soon formed and when the solution above these crystals had lost most of its turbidity, passage of carbon dioxide was discontinued. The crystals were removed by filtration on a steam-jacketed Buchner funnel and Washed on the filter twice with ligroin and three times with acetone. Air was not allowed to pass through the filter cake during the Washing procedure, so as to avoid cooling and consequent condensation of moisture on the filter cake. After the final Washing and before the cake had cooled below the dew point, steam was started through the Buchner jacket and its passage continued until the potassium benzyl carbonate had dried.

My invention will now be described by a reference to the accompanying drawing:

As shown therein a support 10 of any suitable material such as glass, cellulose ester or paper has on it a redsensitive emulsion layer 11 containing a cyan-forming coupler, a green-sensitive emulsion layer 12 containing a magenta-forming coupler, a yellow filter layer 13 and a blue-sensitive emulsion layer 14 containing yellowforming coupler and also containing packets or particles 15 of colloidal material containing colloidal silver and magenta-forming coupler. Upon exposure of this material to white light as indicated, followed by color development in a color developer containing a silver halide solvent and removal of the silver and silver halide, the element appears as shown in the second stage of the drawing. The bottom emulsion layer contains a cyan negative image 16, the middle emulsion contains a magenta negative image 17 and the top emulsion layer contains a yellow negative image 18. The particles 15 in the exposed portions of the top layer form no image because the silver halide is used up in forming the image 18 in the exposed regions of the layer. In the unexposed regions of the top layer a magenta image 19 is formed in the dispersed particles containing the magenta-forming coupler by physical development as described above. Thus a positive magenta image 19 is formed in conjunction with a yellow negative image 18 in the top emulsion ayer.

It will be understood that numerous changes may be made within the purview of my invention and that my invention is to be taken as limited only by the scope of the appended claims.

I claim:

1. An integrally masked, color-forming photographic emulsion layer, comprising a silver halide emulsion sensitive to the blue region of the visible spectrum, containing a dispersion of a color coupler capable of forming upon color development with a primary aromatic amine developing agent a yellow dye image which absorbs a major proportion of blue light and a minor proportion of green light, and individual packets of the ammonium salt of styrene-maleamic acid resin containing colloidal silver and a color coupler capable of forming upon coupling with the developer oxidation product of said primary aromatic amino developing agent a magenta dye absorbing said green light but absorbing no substantial amount of said blue light.

2. A multi-layer photographic element comprising a support having thereon three silver halide emulsion layers sensitive respectively to the red, green and blue spectral regions, said red-sensitive layer containing a dispersion of a color coupler capable of forming a cyan dye image upon color development with a primary aromatic amino developing agent, said green-sensitive layer containing a color coupler capable of forming a magenta dye image upon color development with a primary aromatic amino developing agent and said blue-sensitive layer containing a dispersion of a color coupler capable of forming upon color development with a primary aromatic amino developing agent a yellow dye image which absorbs a major proportion of blue light and a minor proportion of green light, and individual packets of the ammonium salt of styrene-maleamic acid resin containing colloidal silver and a color coupler capable of forming upon coupling with the developer oxidation product of said primary aromatic amino developing agent a magenta dye absorbing said green light but absorbing no substantial amount of said blue light.

3. The method of forming a corrected color separation image in a color-forming photographic emulsion layer, which comprises exposing to an image a silver halide emulsion sensitive to a primary color region of the visible spectrum containing a dispersion of a color coupler capable of forming upon color development with a primary aromatic amino developing agent a yellow dye image which absorbs a major proportion of blue light and a minor proportion of green light and individual packets of the ammonium salt of styrene-malearnic acid resin containing colloidal silver and a color coupler ca pable of forming upon coupling with. the developer oxidation product of said primary aromatic amino developing agent a magenta dye absorbing green light but absorbing no substantial amount of blue light, to form exposed and unexposed portions of said layer, developing said layer in an alkaline solution containing a primary aromatic amino developing agent and a silver halide solvent to form a negative dye image from said first-mentioned coupler in the exposed regions of said layer and a positive dye image from said second-mentioned coupler in the unexposed regions of said layer.

4. The method of forming a corrected color separation image in a color-forming photographic emulsion layer, which comprises exposing to an image a silver halide emulsion sensitive to a primary color region of the visible spectrum containing a dispersion of a color coupler capable of forming upon color development with a primary aromatic amino developing agent a yellow dye image which absorbs a major proportion of blue light and a minor proportion of green light and individual packets of the ammonium salt of styrene-maleamic acid resin containing colloidal silver and a color coupler capable of forming upon coupling with the developer oxidation product of said primary aromatic amino developing agent a magenta dye absorbing green light but absorbing no substantial amount of blue light, to form exposed and unexposed portions of said layer, developing said layer in an alkaline solution containing a primary aromatic amino developing agent and approximately 40 grams per liter of sodium sulfite as a silver halide solvent to form a negative dye image from said first-mentioned coupler in the exposed. regions of said layer and a positive dye image from said second-mentioned coupler in the unexposed regions of said layer.

References Cited in the file of this patent FOREIGN PATENTS 900,266 France Sept. 25, 1944 (3rd addition to No. 873,507)

France July 16, 1945 (4th addition to No; 873,507)

Great Britain Mar. 15, 1950 

1. AN INTEGRALLY MASKED, COLOR-FORMING PHOTOGRAPHIC EMULSION LAYER, COMPRISING A SILVER HALIDE EMULSION SENSITIVE TO THE BLUE REGION OF THE VISIBLE SPECTRUM, CONTAINING A DISPERSION OF A COLOR COUPLER CAPABLE OF FORMING UPON COLOR DEVELOPMENT WITH A PRIMARY AROMATIC AMINE DEVELOPING AGENT A YELLOW DYE IMAGE WHICH ABSORBS A MAJOR PROPORTION OF BLUE LIGHT AND A MINOR PROPORTION OF GREEN LIGHT, AND INDIVIDUAL PACKETS OF THE AMMONIUM SALT OF STYRENE-MALEAMIC ACID RESIN CONTAINING COLLOIDAL SILVER AND A COLOR COUPLER CAPABLE OF FORMING UPON COUPLING WITH THE DEVELOPER OXIDATION PRODUCT OF SAID PRIMARY AROMATIC AMINO DEVELOPING AGENT A MAGENTA DYE ABSORBING SAID GREEN LIGHT BUT ABSORBING NO SUBSTANTIAL AMOUNT OF SAID BLUE LIGHT. 